Long-term Changes in the Main Components of Lake Khanka Water Regime

Abstract

Changes in annual total precipitation and annual pan evaporation for the Lake Khanka water area during the period of 1949–2015 are analyzed based on observational data of weather stations within the lake basin. The reliability of the calculated values of characteristics affecting evaporation changes was confirmed by their comparison with observations at the 20-m2 evaporation pan installed at Astrakhanka lake station. It is shown that against a background of significant interannual fluctuations of annual precipitation during the whole period under study, its trends are almost absent. However, a rather stable increase in annual precipitation value caused by the summer precipitation rise has been noted since the early 2000s. The value of annual pan evaporation decreased from 1949 to 2015, and the rate of its decrease till 1980 was higher than in the next period. Moreover, some evaporation increase has been observed in the recent decade. The main contribution to the evaporation change is made by wind speed changes which cause about 50% of evaporation variance. Air humidity deficit is the second affecting factor that determines a little over 20% of annual evaporation variance. It is demonstrated that the increase in annual precipitation is possible by the middle of the 21st century, while the change in annual evaporation from the Lake Khanka water area would be minimal. Under such changes in the main components of the lake water regime, no reduction of its level due to natural climate processes should be expected.

Scientific Research on Studying Hydrological Features of Lake Khanka Water Regime to Determine Reasons for Abnormal Water Level Rise and to Elaborate Scientifically Grounded Proposals on the Lake Water Level Control and on the Formation of the Set of Measures on Mitigation of Negative Impact of the Lake Water on the Territory of the Primorsky Krai, Part 1: Report on Research Works (Intermediate), Supervised by V. Yu. Georgievskii, No. GR AAAA-A16-116060710003-5; Inv. No. 515-NIR (GGI, St. Petersburg, 2016) [in Russian].Google Scholar